The present invention relates to clutch thrust bearing devices for disc clutches and more particularly for diaphragm clutches. The clutch thrust bearing has a roller bearing which typically includes a rotatable race and a non-rotatable race. In the clutch disengagement action the thrust bearing slides axially on the shaft or a guide tube, and the rotatable bearing race transmits the disengaging stress to the diaphragm.
In a known clutch thrust bearing device, a spring applies pressure to opposite sides of the non-rotatable bearing race and pulls the clutch release fork against the inner race of the thrust bearing to secure the bearing to the release fork. To center the fork, the branches of the fork are located between brackets or similar projections which extend from the inner non-rotatable race of the thrust bearing, the brackets bearing directly on the fork. In this prior structure, the fork is centered in a relatively rigid manner, and each thrust bearing must be designed to coact with a particular size of release fork (see for example French Patent of addition No. 89,929).
An object of the present invention is to provide thrust bearing devices in which the same thrust bearing may be used with clutch release forks having different configurations. It is desired also to provide a clutch thrust bearing device in which the securing spring of the clutch release fork ensures direct elastic centering of the fork relative to the thrust bearing. Still another object is to provide a clutch thrust bearing device in which the spring configuration is such that the thrust bearing is centered relative to the branches of the clutch release fork in a more effective manner than has heretofore been possible.
According to the present invention, the clutch thrust bearing device includes a roller bearing provided with inner and outer races. The inner race has a radial flange. A spring mounted on the radial flange has two fork-contacting portions which bear laterally against the branches of the clutch release fork. The spring alone centers the fork relative to the thrust bearing. The magnitude of fork-centering forces can be modified by changing the configuration of the spring. Furthermore, the invention makes it possible to use one clutch thrust bearing with different clutch release forks having differing dimensions, merely by modifying the spring configuration.
According to a first embodiment of the invention, the fork-contacting portions of the spring contact and bear against the outer faces of the branches of the fork. The spring also bears outwardly on the inner faces of two axial brackets which extend from the radial flange of the inner bearing race.
In another embodiment, the fork-contacting portions of the spring are in direct lateral contact with the inner faces of the branches of the fork.
In the embodiments mentioned above, the spring which ensures direct elastic centering of the fork relative to the thrust bearing acts on the branches of the fork and the faces of axial brackets which extend from the radial flange of the inner race of the roller bearing. In a variant embodiment, the radial flange of the inner race has, in lieu of brackets, diametrically opposed radial recesses which receive the portions of the spring.
In another embodiment the fork-contacting portions of the spring come into direct lateral contact with the inside faces of the branches of the clutch release fork and other portions of the spring loop around to contact the outer faces of axial brackets on the bearing race. In this construction, the spring biases the axial brackets of the radial flange inwardly in opposite directions, toward their respective branches of the clutch release fork.
The invention will be better understood from the following detailed description of some particular embodiments which shall serve to exemplify the invention but not to limit it.